Method and device for cooling a motor vehicle engine

Abstract

A method for cooling a motor vehicle engine which engine consists in regulating the volume and the flow rate of a coolant in a hydraulic circuit provided with a first bypass hose wherein is arranged a water/oil exchanger. The method comprises a first step of regulating the flow rate of the liquid in the first bypass hose to increase the speed of the increase in the temperature of the oil and a second step of regulating the flow rate of the liquid in the first bypass hose to maintain the temperature of the oil at about a reference temperature. The invention also concerns a device for cooling a motor vehicle engine.

1. Method for cooling a motor vehicle engine, which consists in regulating the volume and the flow rate of a cooling fluid in a hydraulic circuit provided with a first branch in which a water/oil exchanger is arranged, the method comprising a first step of regulating the flow rate of the liquid in the first branch to accelerate the speed of the increase in the temperature of the oil, and a second step of regulating the flow rate of the liquid in the first branch to maintain the temperature of the oil around a reference temperature (Tr). 
   
   
     2. Method according to  claim 1 , which comprises a step of determining the temperature (T) of the cooling liquid, and a step of limiting or stopping the circulation of the fluid in the first branch of the circuit when the temperature of the fluid is lower than a specified first threshold temperature (T 1 ). 
   
   
     3. Device for cooling a motor vehicle engine, of the type comprising a hydraulic circuit of a cooling fluid, associated with a pump for circulating the fluid through the engine of the vehicle and different branches of the circuit, in which are arranged thermal equipment of the vehicle, at least some of the branches of the circuit being equipped with electronically controlled actuators to regulate the circulation of the fluid in these branches, the device comprising means for collecting information relating to the operation conditions of the vehicle, connected to means for controlling the operation of the actuators, in order to regulate the volume and the flow rate of the fluid circulating in the hydraulic circuit so as to optimize the operation of the engine, wherein the circuit comprises a first branch equipped with a first actuator and in which is arranged an oil/water exchanger, the control means cooperating with the information collection means, in order to control the opening or closing of the first actuator, so as, on the one hand, to accelerate the speed of the increase in the temperature of the oil and, on the other hand, to regulate the temperature of the oil around a reference temperature (Tr). 
   
   
     4. Device according to  claim 3 , wherein the information collection means are adapted to determine the temperature (T) of the cooling liquid, and the control means ensure the limitation or stop of the circulation of the fluid in the first branch of the circuit when the temperature of the fluid is lower than a specified first threshold temperature (T 1 ). 
   
   
     5. Device according to  claim 3 , wherein the information collection means are adapted to determine the temperature (T) of the cooling liquid and the temperature (Th) of the oil such that, when the temperature (T) of the cooling liquid is higher than a specified second threshold temperature (T 2 ), the control means regulate the temperature of the oil around the reference temperature (Tr) while ensuring, on the one hand, the circulation of the fluid in the first branch when the temperature of the oil exceeds the reference temperature (Tr) by a specified first value (DTa) and, on the other hand, cuts off or limits the circulation of the fluid in the first branch when the temperature of the oil is lower than the reference temperature (Tr) by a value (DTa). 
   
   
     6. Device according to  claim 3 , wherein, when the temperature (T) of the cooling liquid is between the first threshold temperature (T 1 ) and the second threshold temperature (T 2 ), the control means ensure the circulation of the fluid in the first branch only when the temperature (T) of the fluid exceeds the temperature of the oil by a specified second value (DTb). 
   
   
     7. Device according to  claim 5 , wherein the second threshold temperature (T 2 ) is between 60 and 100 degrees C. approximately. 
   
   
     8. Device according to  claim 4 , wherein the first threshold temperature (T 1 ) is between 20 and 60 degrees C. approximately and defines the temperature of the fluid below which the state of the engine is referred to as “cold”. 
   
   
     9. Device according to  claim 4 , wherein the control means cooperate with the collection means, in order to calculate, on the one hand, the average instantaneous power (Pm) supplied by the engine, and then, on the other hand, the first threshold temperature (T 1 ) as a function of the average instantaneous power (Pm) and a specified modeling of the operation of the engine which defines its cold state, including the first threshold temperature (T 1 ), as a function of the average power (Pm). 
   
   
     10. Device according to  claim 5 , wherein the first value (DTa) is on the order of 1 and 6 degrees C. approximately. 
   
   
     11. Device according to  claim 6 , wherein the second value (DTb) is on the order of 10 and 20 degrees C. approximately. 
   
   
     12. Device according to  claim 3 , wherein the reference temperature (Tr) of the oil is between 120 and 140 degrees C. approximately. 
   
   
     13. Device according to  claim 3 , wherein the first actuator is of the type having total opening and closing. 
   
   
     14. Device according to  claim 4 , wherein the information collection means are adapted to determine the temperature (T) of the cooling liquid and the temperature (Th) of the oil such that, when the temperature (T) of the cooling liquid is higher than a specified second threshold temperature (T 2 ), the control means regulate the temperature of the oil around the reference temperature (Tr) while ensuring, on the one hand, the circulation of the fluid in the first branch when the temperature of the oil exceeds the reference temperature (Tr) by a specified first value (DTa) and, on the other hand, cuts off or limits the circulation of the fluid in the first branch when the temperature of the oil is lower than the reference temperature (Tr) by a value (DTa). 
   
   
     15. Device according to  claim 4 , wherein, when the temperature (T) of the cooling liquid is between the first threshold temperature (T 1 ) and the second threshold temperature (T 2 ), the control means ensure the circulation of the fluid in the first branch only when the temperature (T) of the fluid exceeds the temperature of the oil by a specified second value (DTb). 
   
   
     16. Device according to  claim 6 , wherein the second threshold temperature (T 2 ) is between 60 and 100 degrees C. approximately. 
   
   
     17. Device according to  claim 14 , wherein the second threshold temperature (T 2 ) is between 60 and 100 degrees C. approximately. 
   
   
     18. Device according to  claim 15 , wherein the second threshold temperature (T 2 ) is between 60 and 100 degrees C. approximately. 
   
   
     19. Device according to  claim 6 , wherein the first threshold temperature (T 1 ) is between 20 and 60 degrees C. approximately and defines the temperature of the fluid below which the state of the engine is referred to as “cold”. 
   
   
     20. Device according to  claim 15 , wherein the first threshold temperature (T 1 ) is between 20 and 60 degrees C. approximately and defines the temperature of the fluid below which the state of the engine is referred to as “cold”. 
   
   
     21. Device according to  claim 6 , wherein the control means cooperate with the collection means, in order to calculate, on the one hand, the average instantaneous power (Pm) supplied by the engine, and then, on the other hand, the first threshold temperature (T 1 ) as a function of the average instantaneous power (Pm) and a specified modeling of the operation of the engine which defines its cold state, including the first threshold temperature (T 1 ), as a function of the average power (Pm). 
   
   
     22. Device according to  claim 8 , wherein the control means cooperate with the collection means, in order to calculate, on the one hand, the average instantaneous power (Pm) supplied by the engine, and then, on the other hand, the first threshold temperature (T 1 ) as a function of the average instantaneous power (Pm) and a specified modeling of the operation of the engine which defines its cold state, including the first threshold temperature (T 1 ), as a function of the average power (Pm). 
   
   
     23. Device according to  claim 15 , wherein the control means cooperate with the collection means, in order to calculate, on the one hand, the average instantaneous power (Pm) supplied by the engine, and then, on the other hand, the first threshold temperature (T 1 ) as a function of the average instantaneous power (Pm) and a specified modeling of the operation of the engine which defines its cold state, including the first threshold temperature (T 1 ), as a function of the average power (Pm). 
   
   
     24. Device according to  claim 19 , wherein the control means cooperate with the collection means, in order to calculate, on the one hand, the average instantaneous power (Pm) supplied by the engine, and then, on the other hand, the first threshold temperature (T 1 ) as a function of the average instantaneous power (Pm) and a specified modeling of the operation of the engine which defines its cold state, including the first threshold temperature (T 1 ), as a function of the average power (Pm). 
   
   
     25. Device according to  claim 20 , wherein the control means cooperate with the collection means, in order to calculate, on the one hand, the average instantaneous power (Pm) supplied by the engine, and then, on the other hand, the first threshold temperature (T 1 ) as a function of the average instantaneous power (Pm) and a specified modeling of the operation of the engine which defines its cold state, including the first threshold temperature (T 1 ), as a function of the average power (Pm). 
   
   
     26. Device according to  claim 6 , wherein the first value (DTa) is on the order of 1 and 6 degrees C. approximately. 
   
   
     27. Device according to  claim 15 , wherein the first value (DTa) is on the order of 1 and 6 degrees C. approximately. 
   
   
     28. Device according to  claim 15 , wherein the second value (DTb) is on the order of 10 and 20 degrees C. approximately. 
   
   
     29. Device according to  claim 4 , wherein the reference temperature (Tr) of the oil is between 120 and 140 degrees C. approximately. 
   
   
     30. Device according to  claim 4 , wherein the first actuator is of the type having total opening and closing. 
   
   
     31. Device according to  claim 10 , wherein the first value (DTa) is equal to two degrees C. 
   
   
     32. Device according to  claim 11 , wherein the second value (DTb) is equal to 15 degrees C. 
   
   
     33. Device according to  claim 12 , wherein the reference temperature (Tr) of the oil is equal to 130 degrees C. approximately.